Selective Catalytic Reduction of NOx

1. of NOx from Exhaust Stack

8. 1999 National Emissions by Source: Nitrogen Oxides 1999 National Emissions by Source: Nitrogen Oxides (On-Road Mobile Sources) 1999 National Emissions by Source: Nitrogen Oxides (Nonroad Mobile Sources Source: http://www.epa.gov/oms/invntory/overview/pollutants/nox.htm

10. SCR – The Process Engine: The NOx reduction process starts with an efficient CRD engine design that burns clean Ultra Low Sulfur Diesel (ULSD) and produces inherently lower exhaust emissions—exhaust that is already much cleaner due to leaner and more complete combustion. Diesel Exhaust Fluid (DEF) tank and pump: Under the direction of the vehicle’s onboard computer, DEF is delivered in precisely metered spray patterns into the exhaust stream just ahead of the SCR converter. Source: About.com

11. SCR – The Process SCR Catalytic Converter: This is where the conversion happens. Exhaust gases and an atomized mist of DEF enter the converter simultaneously. Together with the catalyst inside the converter, the mixture undergoes a chemical reaction that produces nitrogen gas and water vapor. Control device: Exhaust gases are monitored via a sensor as they leave the SCR catalyst. Feedback is supplied to the main computer to alter the DEF flow if NOx levels fluctuate beyond acceptable parameters. Source: About.com

20. SCR – The Process

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